1. Technical Field
The present invention relates broadly to stairway ramps and more particularly relates to a modular ramp for stairways of any required length.
2. The Prior Art
Heretofore, stairway ramps have been rather crude devices ranging from a simple pair of laterally adjustable parallel tracks of fixed length in U.S. Pat. No. 1,505,116 to length-adjustable stairway ramps in U.S. Pat. Nos. 3,009,183 and 4,528,711.
No one in the prior art appears to have recognized the important advantage from a safety and stability viewpoint of utilizing the right angular recesses formed by the treads and risers of steps to seat a stairway ramp so that the same cannot slide dangerously on the stairway. In attempting to deal with this in the prior art cumbersome extensions are sometimes provided on the ends of the ramp to engage level floor surfaces and resist slipping, as in U.S. Pat. Nos. 981,613 and 3,009,183.
The present invention involves two major advances in the construction of stairway ramps for hand trucks, wheelchairs and the like, the first of which is forming the ramp in multiple right triangular hollow sections which nest securely into the recesses formed by the steps and the second of which is the formation of the stairway ramp in separate easily connectable and separable step modules which collectively form a pair of parallel laterally adjustable continuous inclined ramp trackways along a stairway of any required length.
The stairway ramp according to the present invention is therefore much safer than known prior art ramps in that it cannot slip along the stairway. The necessity for floor-engaging end terminals on the ramp is eliminated. Moreover, the ramp is much more versatile than prior art types due to its modular construction whereby it can be installed on very short or very long stairways and dismantled for much more compact storage.
Other important features and objects of the invention will become apparent to those skilled in the art during the course of the following detailed description.